中文摘要：

地层压力是计算气藏储量、评价气井产能、进行动态分析等必不可少的重要参数。根据定容性封闭气藏物质平衡方程，在已知天然气组分、地层温度、井底流压及产量等条件下，通过偏差因子程序计算得到地层温度恒定条件下井底流压对应的气体偏差因子，从而做累计产气量与井底视地层压力关系曲线并做其拟合直线，再通过已知视地层压力，做拟合直线的平行线，得到任意时刻累计产气量对应气藏视地层压力的关系曲线，利用此曲线预测在一定生产制度下地层压力变化趋势。应用表明该方法简单实用，计算地层压力接近实测地层压力，减轻现场测试工作量。

英文摘要：

Formation pressure is an indispensable and important parameter for gas reserves calculation, gas well productivity evaluation and dynamic analysis. According to the constant volume closed gas reservoir matter balance equation, with given natural gas components, formation temperature, bottom hole flow pressure and output, the deviation factor for gas corresponding to bottom hole flow pressure is calculated through deviation factor program calculation under constant formation temperature. Then, through the already known apparent formation pressure, a parallel line to the fitting straight and corresponding sure change trend line is drawn, so that the correlation curve of accumulated gas production rate at any given time apparent formation pressure can be derived. The correlation curve is used to predict formation presunder certain production system. The method is simple and applicable; the calculated formation pressure is close to the measured data. The method reduces the measurement work amount in field.